make plots less dense, enable plotting for igraph (networkx#4791)

Make igraph plotting example render in gallery

examples/external/plot_igraph.py

@@ -15,30 +15,37 @@
 # NetworkX to igraph
 # ------------------
 
-G = nx.dense_gnm_random_graph(1000, 2000)
+G = nx.dense_gnm_random_graph(30, 40, seed=42)
 
 # largest connected component
 components = nx.connected_components(G)
 largest_component = max(components, key=len)
 H = G.subgraph(largest_component)
 
-# networkx draw
-nx.draw(H)
-plt.show()
-
 # convert to igraph
-g = ig.Graph.from_networkx(G)
+h = ig.Graph.from_networkx(H)
+
+
+# Plot the same network with NetworkX and igraph
+fig, (ax0, ax1) = plt.subplots(nrows=1, ncols=2, figsize=(12, 6))
+
+# NetworkX draw
+ax0.set_title("Plot with NetworkX draw")
+nx.draw_kamada_kawai(H, node_size=50, ax=ax0)
 
-## TODO: uncomment this once python-igraph 0.9 is released
 # igraph draw
-# layout = g.layout()
-# ig.plot(g, layout=layout)
+ax1.set_title("Plot with igraph plot")
+layout = h.layout_kamada_kawai()
+ig.plot(h, layout=layout, target=ax1)
+plt.axis("off")
+plt.show()
+
 
 # %%
 # igraph to NetworkX
 # ------------------
 
-g = ig.Graph.GRG(100, 0.2)
+g = ig.Graph.GRG(30, 0.2)
 G = g.to_networkx()
-nx.draw(G)
+nx.draw(G, node_size=50)
 plt.show()

requirements/example.txt

@@ -3,4 +3,4 @@ momepy>=0.4
 contextily>=1.0
 seaborn>=0.11
 cairocffi>=1.2
-python-igraph>=0.8.3
+python-igraph>=0.9